Comparative investigation of sensor application of polypyrrole for gaseous analytes

Conducting organic polymers (COPs) are excellent candidates for sensor application. Polypyrrole is much superior in this regard than other COPs. A few studies indicate the potential of polypyrrole for some specific analytes; however, global picture of sensitivity and selectivity of polypyrrole sensor for various common analytes remains unclear. Here, we present first comprehensive study of polypyrrole sensors for various analytes: NH3, CO2, CO, N2H4, HCN, H2O2, H2S, CH4, CH3OH, SO2, SO3, and H2O. Geometric, thermodynamic, and electronic properties are calculated for infinite polymer to realize the sensor application of polypyrrole. The strongest interaction energy is observed for nPy‐N2H4 followed by nPy‐SO2/SO3 complexes. However, the interaction energy, charge transfer, FMO analysis, density‐of‐states, and electronic transitions envision the highest response toward SO2 and SO3. Surprisingly, the electronic properties of N2H4 complexes show quite opposite behavior than interaction energy. The uneven behavior of electronic properties for hydrazine is due to the interaction from two different sites which decreases the charge transfer. The excellent geometric and electronic properties related to the oxides of sulfur reveal that polypyrrole is highly selective toward SO2 and SO3. The sensing abilities of oligopyrrole is reported for the detection of NH3, CO2, CO, N2H4, HCN, H2O2, H2S, CH4, CH3OH, SO2, SO3, and H2O. The results are extrapolated to infinite repeating units via 2nd order polynomial fit. Polypyrrole shows superior sensitivity for oxides of sulfur including SO2 and SO3.